I am trying to apply a stylesheet to a custom stylesheet but cannot get the styling to be applied.

class FooterButtonsWidget(QWidget):
    # Footer widget with buttons + icons to other views
    def __init__(self):
        super().__init__()
        self.setObjectName("footerButtonsWidget")       # Set obj name to apply CSS stylesheet directly
        layout = QHBoxLayout(self)

        self.dragon_button = self.create_icon_button("images/spacex_images/dragon-button-icon.png")
        self.fh_button = self.create_icon_button("images/spacex_images/fh-button-icon.png")
        self.apod_button = self.create_icon_button("images/nasa_images/nasa-button.png")
        self.rover_button = self.create_icon_button("images/nasa_images/rover-button-icon.png")
        self.spacex_button = self.create_icon_button("images/spacex_images/spacex-button-icon.png")

        layout.addWidget(self.dragon_button)
        layout.addWidget(self.fh_button)
        layout.addWidget(self.apod_button)
        layout.addWidget(self.rover_button)
        layout.addWidget(self.spacex_button)

        self.setMinimumHeight(100)

        # Have also tried just #footerButtonsWidget, without the QWidget
        self.setStyleSheet("""
            QWidget#footerButtonsWidget {
                border-top: 2px solid white;
                border-right: 2px solid white;
                border-left: 2px solid white;
            }
        """)

I want a border around the footerButtonsWidget widget, so I can have a border around the whole layout, except the bottom. The image below is what I currently have:

Image of what the footerButtonsWidget looks like

And this is what I want to achieve:

Image of what I want footerButtonsWidget to look like

I was able to apply styling to a widget within footerButtonsWidget (following this similar question) by doing

        self.widget = QWidget(self)
        layout.addWidget(self.widget)
        self.widget.setStyleSheet("""
            QWidget {
                border-top: 2px solid white;
            }
        """)

Which gave the border styling like I wanted, but I need the styling to be applied to the whole widget itself and not the widget elements inside of the footerButtonsWidget